1. Field of the Invention
The present invention relates to capacitors and methods for manufacturing capacitors. In particular, the present invention relates to a capacitor including a pair of signal terminals and a grounding terminal and a method for manufacturing the capacitor.
2. Description of the Related Art
The following capacitors are conventionally known: three-terminal capacitors disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2000-107658 and other documents. A three-terminal capacitor typically includes a ceramic body having a substantially cuboid shape. The ceramic body includes first internal electrodes and second internal electrodes. The first internal electrodes and second internal electrodes are arranged in the ceramic body so as to face each other. One of the end surfaces of the ceramic body is overlaid with a first signal terminal and the other is overlaid with a second signal terminal. The first and second signal terminals are connected to the first internal electrodes. The second internal electrodes are connected to a grounding terminal which is disposed on a portion of a side surface of the ceramic body and which is connected to the ground potential.
Each of the first and second signal terminals and the grounding terminal includes a calcined layer disposed on the ceramic body and at least one plating layer disposed on the calcined layer.
The calcined layers of the first and second signal terminals are formed in such a manner that the ceramic body is mechanically positioned and a conductive paste is applied to the ceramic body and then calcined. It is extremely difficult to mechanically apply the conductive paste to the ceramic body with high positional accuracy. Therefore, the first and second signal terminals must be larger than exposed portions of the first and second internal electrodes such that the exposed portions of the first and second internal electrodes are securely covered with the first and second signal terminals. In other words, the exposed portions of the first and second internal electrodes must be smaller than the first and second signal terminals.
Since the first and second signal terminals include the calcined layers, the exposed portions of the first and second internal electrodes must be relatively small, as described above. Therefore, junctions between the second internal electrodes and the grounding terminal are likely to have a reduced electrode cross-sectional area. The reduction in electrode cross-sectional area of the junctions between the second internal electrodes and the grounding terminal causes an increase in ESL, resulting in the insertion loss characteristics being deteriorated.